Harnessing the heat of the earth
Geothermal resources are reservoirs of hot water that exist or are human made at varying temperatures and depths below the Earth’s surface. Wells, ranging from a few feet to several miles deep, can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface for use in heating and cooling.
A pair of wells (known as a doublet) up to 5km deep are drilled into underground reservoirs containing brine (very salty, undrinkable, water).
One of the wells is used to tap into the geothermal resource by pumping the hot water to the surface where the heat is transferred to the surface system through a heat exchanger. The brine is then returned to the reservoir through the second well.
The water in the surface system, after being heated by passing through the heat exchanger, can be utilised for a district heating network or for directly connecting to other customers networks.